A researcher would like to map the location of galE and trpA genes in a new species of bacterium that appears to be closely related to E. coli. He decides to use cotransduction, and generatesnappropriate donor and recipient strains. He is disappointed when cotransduction is not seen in his experiement. What is the most reasonable explanation for this situation?

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#Question id: 13189

#Unit 10. Ecological Principles

The relative abundance of C plant species increases with latitude because of the associated temperature gradient. A study in North America found that at  42°  North,  C3  plants  become more  abundant than  C4  plants. Given  an  increase in  mean global  temperatures by  10°C and no  other changes in  environmental conditions,  the latitude at which C3 plants become more abundant:

TLS Online TPP Program

#Question id: 13190

#Unit 10. Ecological Principles

During the evolution of life on Earth, the photosynthetic organisms initially responsible for raising atmospheric oxygen concentrations from less than 1 percent to about 20 percent were

TLS Online TPP Program

#Question id: 13191

#Unit 10. Ecological Principles

Which of the following statements about circadian rhythms is correct?

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#Question id: 13192

#Unit 10. Ecological Principles

In the schematic below, the left panel represents climatic zones occupied by two different biomes, X and Y, along gradients of temperature and precipitation. The right panel depicts the expected species-area relationships of these two biomes. From the figures below, which of the following are most likely to be true?

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#Question id: 13193

#Unit 1. Molecules and their Interaction Relevant to Biology

Data, collected from DNAs of a great many different species, led Chargaff to the following conclusions:

A. The base composition of DNA generally varies from one species to another.

B. DNA specimens isolated from different tissues of the same species have the different base composition.

C. The base composition of DNA in a given species changes with an organism’s age, nutritional state, or changing environment.

D. In all cellular DNAs, the sum of the purine residues equals the sum of the pyrimidine residues.

Which of the above statements are INCORRECT regarding Chargaff’s rule?

TLS Online TPP Program

#Question id: 13194

#Unit 1. Molecules and their Interaction Relevant to Biology

If we have the sequence 5’-ATGTC-3’ on one chain, the opposite chain must have the complementary sequence